Treating insoluble indigoid dyes.



mmonr mr'rznnn, or LnnwmsnArEn-ou-rnE-nnmn, GERMANY, Asswnon 'ro. rnmscnn mm &' SODA'FA/BRIK, or nrmwresnnjrnu-on-rnn-nnmn, GER- MANY, A GOBPORATION OF 1,188,543. NoDrawing.

To all whom itmwy concern Be it known that I, Rononr HU'TZLER, citizen of the German Empire, residing at Ludwigshafen-on-the-Rhine, Germany, have invented new and useful Improvements in Treating Insoluble Indigoid Dyes, of which the following is a specification. p

The specification of Patents Nos. 1,058,019,

1,058,020 and 1,057,886 describe the produc tion of finely divided indigoid dyestuflts byproducing the said dyes from their'leuco 1 compounds in the presence of aromatic com.-

for instance benzylat e'd acids, 'inpounds,

benzyl sulfanilic acid and benzyleluding anilin sulfonic acid, and also in the presence of aldehydes or phenols and the like; I The specification of the said Patent No. 1,058,019

' also claims as a new product the physical goid coloring matters, that is to say coloring I form of indigo which, when made into a and diluted withwater, yields a deep,- blue liquid settling with difliculty'and giving paste a blue filtrate when filtratd. I I have now found that I can obtain indimatters of the indigo and thioindigo groups,

in a colloidal form soluble in water, that isto say in such a form that the said coloring matters do not settle at all and cannot be separated by-filtration from their alkaline or neutral solutions, including solutions suchas are produced according to the present invention. In order to secure these results, I pass air through a cold solution of a leuco compound of one of the said coloring matters infthe presence of a salt of aromatic acid including aromatic sulfonic acids and carboxylic acids, the reaction being car.- ried out so slowly that only an oxidationto,

but not a separation of the coloring matter takes" lace.- As aromatic acids being particular y suitable .for use according to myinvention I mention benz'ylated aminos'ulfonic acids, phenol-sulfonic acids and also xcondensation products obtained from phe and also soluble aromatic phenolic hydroxyl group and which can be le, according to .the' ritish application for. Patent :No, 7137113 from? naphthalenesul-f nol-sulfonic acids-either wither without the,

assistanceof formaldehyde, as described for instance in h for patent Serial Nos.; 716 ',0 20 and 743,297,

an'amorphous character which contain no obtained,.,' for, 1 exam specificationof-the;

the specifications of applications.

sulfonic' acids of TREATING INSOLUBLE DYESm I Specification of Letters Ifatent, Patented 1 1118 1916. f Application filed September 26, 1913. .Serial No; 791,948.

Q I 7 fonic acids and formaydehydeand the like. .Theresultmgisolutlon or product obtained as aforesaid c'ontainsthe' coloring matter in 7 a state of fine "division such that the colormatter has no tendency to settle out "of the solutlon. This solution can be evaporated. or the coloring matter can be precipitatedyby meansof acid without its c'apability of dissolving in water-being 10st,".

trate further the nature of my invention and how it can be carried into practical effect, but the invention is not confined to these examples.

' Example 1: Dissolve 3' kilos'of the sodium 1 I indigo-white, corresponding to 6 kilos of indigo, to flow into' the solution during a. period of about 48 hours. Filter the. S0111:-

tion obtained,-wash it in an osmotic a pa ratusand then evaporate it, The in igo i obtained can be precipitatedfromthe solution by means of acid without losing its capability of forming an unfilterable solu- Example 2: Dissolve 2.5kilos of the'neutralized reaction product of formaldehyde 60'kilos of a'10% sodium salt-indigo-white solution (corresponding to 6 kilos of indigo) tion in;water. In a similar manner, other 'aromatlc 'sulfonic acids of. the kind herein-1 before described can be'employed. I

to run in while stirring and blowing acur- .rent of air through the mixture, Then filter the bluesolution so obtained, wash it in an osmotic apparatus, andevaporate it to dry- I I ness.

and then during a period'of 48 hoursallow Example 3-: Dissolve 3 kilos of the reacf, tion product of formaldehyde and naphtha lene-betasulfonic acid in 30 liters of water and 1 kilo ofa 10% caustic soda solution,

60 kilos of a 10% solution-{of the sodium salt,

of indigowhite to run inlwhile stirring the current ofair through it. Filter theresul'te 105 mixture continuously and passinga slow 1 ing solution through calico, acidify the fil- I ,1

trate with dilute acetic acid whereupon the indigo is precipitated and filter off the indigo by means of felt; wash the pasty filter residue in anosmotic apparatus whereby the precipitated colloidal indigo goes into solution and evaporate the solution obtained to dryness.

The Washing in the osmotic apparatus I can, for instance, be effected by placing the pasty precipitated indigo from the filter into avessel with parchment walls, surrounded by. a second vessel through which Warm water is circulating.

Now what I claim is 1. The process of producing indigoid coloring matters in a coloidal form soluble r in water by passing air through a cold solution of a leuco compound of one of the said coloring matters in the presence of a salt of an aromatic acid, the air being passed so slowly through the solution that an oxidation to the coloring matter is effected, but a separation of the coloring matter is avoided.

2. The process of producing indigoid coloring matters in a coloidal form soluble in water by passing air through a cold solution of a leuco compound of one of the said l coloring matters in the presence of a salt of an aromatic sulfonic acid, the .air being passed so slowly through the solution that anoxidation to the coloring matter is cf; fected, but a separation of the coloring matter is avoided.

3. The process of producing indigoid coloring matters in a colloidal form soluble in water by passing air through a cold solution of a leuco compound of one of the said coloring matters in the presence of a. salt of a benzylated amin sulfonic acid, the air being passed so slowly through the solution that an oxidation to indigo is effected, but a separation of the indigo from the solution is avoided. 1

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

RUDOLE HUTZLE-R.

Witnesses: I

' J. Anne. LLOYD,

Josnrn PFEIFFER. 

